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csutil/csendian.h
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00001 /*
00002     Copyright (C) 1998 by Jorrit Tyberghein
00003 
00004     This library is free software; you can redistribute it and/or
00005     modify it under the terms of the GNU Library General Public
00006     License as published by the Free Software Foundation; either
00007     version 2 of the License, or (at your option) any later version.
00008 
00009     This library is distributed in the hope that it will be useful,
00010     but WITHOUT ANY WARRANTY; without even the implied warranty of
00011     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012     Library General Public License for more details.
00013 
00014     You should have received a copy of the GNU Library General Public
00015     License along with this library; if not, write to the Free
00016     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00017 */
00018 
00019 #ifndef __CS_CSENDIAN_H__
00020 #define __CS_CSENDIAN_H__
00021 
00029 #include <math.h>
00030 #include "cstypes.h"
00031 #include "csgeom/math.h"
00032 #include "csutil/bitops.h"
00033 #if defined(CS_HAVE_BYTESWAP_H)
00034 #include <byteswap.h>
00035 #endif
00036 
00037 #define csQroundSure(x) (int ((x) + ((x < 0) ? -0.5 : +0.5)))
00038 
00042 struct csSwapBytes
00043 {
00044 public:
00046 
00047   static CS_FORCEINLINE uint16 Swap (uint16 s) 
00048   { 
00049   #if defined(CS_COMPILER_MSVC) && (_MSC_VER >= 1300)
00050     return _byteswap_ushort (s);
00051   #elif defined(CS_HAVE_BYTESWAP_H)
00052     return bswap_16 (s);
00053   #else
00054     return (s >> 8) | (s << 8); 
00055   #endif
00056   }
00057   static CS_FORCEINLINE int16  Swap (int16 s)
00058   { return (int16)Swap ((uint16)s); }
00059   static CS_FORCEINLINE uint32 Swap (uint32 l)
00060   { 
00061   #if defined(CS_COMPILER_MSVC) && (_MSC_VER >= 1300)
00062     return _byteswap_ulong (l);
00063   #elif defined(CS_HAVE_BYTESWAP_H)
00064     return bswap_32 (l);
00065   #else
00066     return (l >> 24) | ((l >> 8) & 0xff00) | ((l << 8) & 0xff0000) | (l << 24); 
00067   #endif
00068   }
00069   static CS_FORCEINLINE int32  Swap (int32 l)
00070   { return (int32)Swap ((uint32)l); }
00071   static CS_FORCEINLINE uint64 Swap (uint64 l)
00072   {
00073   #if defined(CS_COMPILER_MSVC) && (_MSC_VER >= 1300)
00074     return _byteswap_uint64 (l);
00075   #elif defined(CS_HAVE_BYTESWAP_H) && !defined(__STRICT_ANSI__)
00076     return bswap_64 (l);
00077   #else
00078     union
00079     {
00080       uint64 ui64;
00081       uint32 ui32[2];
00082     } u1, u2;
00083     u1.ui64 = l;
00084     u2.ui32[0] = Swap (u1.ui32[1]);
00085     u2.ui32[1] = Swap (u1.ui32[0]);
00086     return u2.ui64;
00087   #endif
00088   }
00089   static CS_FORCEINLINE int64  Swap (int64 l)
00090   { return (int64)Swap ((uint64)l); }
00091   
00092   static CS_FORCEINLINE uint16 UInt16 (uint16 x) { return Swap (x); }
00093   static CS_FORCEINLINE int16  Int16  (int16 x)  { return Swap (x); }
00094   static CS_FORCEINLINE uint32 UInt32 (uint32 x) { return Swap (x); }
00095   static CS_FORCEINLINE int32  Int32  (int32 x)  { return Swap (x); }
00096   static CS_FORCEINLINE uint64 UInt64 (uint64 x) { return Swap (x); }
00097   static CS_FORCEINLINE int64  Int64  (int64 x)  { return Swap (x); }
00099 };
00100 
00101 #ifdef CS_BIG_ENDIAN
00102 struct csBigEndian
00103 #else
00109 struct csLittleEndian
00110 #endif
00111 {
00113 
00114   static CS_FORCEINLINE uint16 Convert (uint16 x) { return x; }
00115   static CS_FORCEINLINE int16  Convert (int16 x)  { return x; }
00116   static CS_FORCEINLINE uint32 Convert (uint32 x) { return x; }
00117   static CS_FORCEINLINE int32  Convert (int32 x)  { return x; }
00118   static CS_FORCEINLINE uint64 Convert (uint64 x) { return x; }
00119   static CS_FORCEINLINE int64  Convert (int64 x)  { return x; }
00120   
00121   static CS_FORCEINLINE uint16 UInt16 (uint16 x) { return Convert (x); }
00122   static CS_FORCEINLINE int16  Int16  (int16 x)  { return Convert (x); }
00123   static CS_FORCEINLINE uint32 UInt32 (uint32 x) { return Convert (x); }
00124   static CS_FORCEINLINE int32  Int32  (int32 x)  { return Convert (x); }
00125   static CS_FORCEINLINE uint64 UInt64 (uint64 x) { return Convert (x); }
00126   static CS_FORCEINLINE int64  Int64  (int64 x)  { return Convert (x); }
00128 };
00129 
00130 #ifdef CS_LITTLE_ENDIAN
00131 
00136 struct csBigEndian
00137 #else
00138 struct csLittleEndian
00139 #endif
00140 {
00141 public:
00143 
00144   static CS_FORCEINLINE uint16 Convert (uint16 s) 
00145   { return csSwapBytes::Swap (s); }
00146   static CS_FORCEINLINE int16  Convert (int16 s)
00147   { return csSwapBytes::Swap (s); }
00148   static CS_FORCEINLINE uint32 Convert (uint32 l)
00149   { return csSwapBytes::Swap (l); }
00150   static CS_FORCEINLINE int32  Convert (int32 l)
00151   { return csSwapBytes::Swap (l); }
00152   static CS_FORCEINLINE uint64 Convert (uint64 l)
00153   { return csSwapBytes::Swap (l); }
00154   static CS_FORCEINLINE int64  Convert (int64 l)
00155   { return csSwapBytes::Swap (l); }
00156   
00157   static CS_FORCEINLINE uint16 UInt16 (uint16 x) { return Convert (x); }
00158   static CS_FORCEINLINE int16  Int16  (int16 x)  { return Convert (x); }
00159   static CS_FORCEINLINE uint32 UInt32 (uint32 x) { return Convert (x); }
00160   static CS_FORCEINLINE int32  Int32  (int32 x)  { return Convert (x); }
00161   static CS_FORCEINLINE uint64 UInt64 (uint64 x) { return Convert (x); }
00162   static CS_FORCEINLINE int64  Int64  (int64 x)  { return Convert (x); }
00164 };
00165 
00169 struct csIEEEfloat
00170 {
00171   /* \todo It would be even better if we also check for sizeof (float)
00172    * in configure or so. */
00173 #ifdef CS_IEEE_DOUBLE_FORMAT
00174 
00175 
00176   static CS_FORCEINLINE uint32 FromNative (float f)
00177   { 
00178     union
00179     {
00180       float f;
00181       uint32 ui32;
00182     } u;
00183     u.f = f;
00184     return u.ui32; 
00185   }
00186   static CS_FORCEINLINE uint64 FromNative (double f)
00187   { 
00188     union
00189     {
00190       double f;
00191       uint64 ui64;
00192     } u;
00193     u.f = f;
00194     return u.ui64; 
00195   }
00197 
00199 
00200   static CS_FORCEINLINE float ToNative (uint32 f)
00201   { 
00202     union
00203     {
00204       float f;
00205       uint32 ui32;
00206     } u;
00207     u.ui32 = f;
00208     return u.f; 
00209   }
00210   static CS_FORCEINLINE double ToNative (uint64 f)
00211   { 
00212     union
00213     {
00214       double f;
00215       uint64 ui64;
00216     } u;
00217     u.ui64 = f;
00218     return u.f; 
00219   }
00221 #else
00222   #error Do not know how to convert to IEEE floats
00223 #endif
00224 
00226   static CS_FORCEINLINE float ToNative (uint16 half)
00227   {
00228     union
00229     {
00230       uint32 u;
00231       float f;
00232     } u2f;
00233 
00234     uint32 sign = (half & 0x8000) << 16;
00235     int32 exponent = (half & 0x7C00) >> 10;
00236     uint32 mantissa = (half & 0x03ff) << 13;
00237    
00238     // Check for INF or NaN.
00239     if (exponent == 0x1F)
00240     {
00241       u2f.u = sign | mantissa;
00242 
00243       if (mantissa != 0)
00244       {
00245         // NaN
00246         u2f.u |= 0x7FC00000;
00247       }
00248       else
00249       {
00250         // INF
00251         u2f.u |= 0x7f800000;
00252       }
00253 
00254       return u2f.f;
00255     }
00256 
00257     // Check for a denorm.
00258     if(exponent == 0)
00259     {
00260       unsigned long index;
00261       CS::Utility::BitOps::ScanBitReverse (mantissa, index);
00262 
00263       exponent -= (index - 9);
00264       mantissa <<= (index - 8);
00265       mantissa &= 0x007FFFFF;
00266     }
00267 
00268     // Convert the exponent...
00269     exponent += 112;
00270     exponent <<= 23;
00271 
00272     // And create the float...
00273     u2f.u = sign | exponent | mantissa;
00274 
00275     return u2f.f;
00276   }
00277 
00282   static CS_FORCEINLINE uint16 FromNativeRTZ (float f)
00283   {
00284     union
00285     {
00286       float f;
00287       unsigned int u;
00288     } f2u;
00289 
00290     f2u.f = f;
00291     unsigned short sign = 0x8000 & (f2u.u >> 16);
00292 
00293     // Get the absolute value.
00294     f2u.u &= 0x7FFFFFFF;
00295 
00296     // Check for a NaN
00297     if(CS::IsNaN (f2u.f))
00298     {
00299       // Construct a silent NaN.
00300       f2u.u >>= 13;
00301       f2u.u &= 0x7fff;
00302       f2u.u |= 0x0200;
00303       return sign | f2u.u;
00304     }
00305 
00306     // Check for overflow.
00307     if(f2u.u >= 0x47800000)
00308     {
00309       // Check for INF.
00310       if(f2u.u == 0x7F800000)
00311         return sign | 0x7C00;
00312 
00313       return sign | 0x7BFF;
00314     }
00315 
00316     // Check for underflow and denorms (flush to zero).
00317     if(f2u.u < 0x38800000)
00318       return sign;
00319 
00320     // Convert the float to a half (rounding to zero).
00321     f2u.u &= 0xFFFFE000U;
00322     f2u.u -= 0x38000000U;
00323     return sign | (f2u.u >> 13);
00324   }
00325 };
00326 
00335 struct csGetFromAddress
00336 {
00338 
00339   static CS_FORCEINLINE uint16 UInt16 (const void *buff)
00340   {
00341   #ifdef CS_STRICT_ALIGNMENT
00342     uint16 s; memcpy (&s, buff, sizeof (s));
00343     return s;
00344   #else
00345     return *(uint16 *)buff;
00346   #endif
00347   }
00348   static CS_FORCEINLINE int16  Int16 (const void *buff)
00349   { return (int16)UInt16 (buff); }
00350   static CS_FORCEINLINE uint32 UInt32 (const void *buff)
00351   {
00352   #ifdef CS_STRICT_ALIGNMENT
00353     uint32 s; memcpy (&s, buff, sizeof (s));
00354     return s;
00355   #else
00356     return *(uint32 *)buff;
00357   #endif
00358   }
00359   static CS_FORCEINLINE int32  Int32 (const void *buff)
00360   { return (int32)UInt32 (buff); }
00361   static CS_FORCEINLINE uint64 UInt64 (const void *buff)
00362   {
00363   #ifdef CS_STRICT_ALIGNMENT
00364     uint64 s; memcpy (&s, buff, sizeof (s));
00365     return s;
00366   #else
00367     return *(uint64 *)buff;
00368   #endif
00369   }
00370   static CS_FORCEINLINE int64  Int64 (const void *buff)
00371   { return (int64)UInt64 (buff); }
00373 };
00374 
00383 struct csSetToAddress
00384 {
00386 
00387   static CS_FORCEINLINE void UInt16 (void *buff, uint16 s)
00388   {
00389   #ifdef CS_STRICT_ALIGNMENT
00390     memcpy (buff, &s, sizeof (s));
00391   #else
00392     *((uint16 *)buff) = s;
00393   #endif
00394   }
00395   static CS_FORCEINLINE void Int16  (void *buff, int16 s)
00396   { UInt16 (buff, (uint16)s); }
00397   static CS_FORCEINLINE void UInt32 (void *buff, uint32 s)
00398   {
00399   #ifdef CS_STRICT_ALIGNMENT
00400     memcpy (buff, &s, sizeof (s));
00401   #else
00402     *((uint32 *)buff) = s;
00403   #endif
00404   }
00405   static CS_FORCEINLINE void Int32  (void *buff, int32 s)
00406   { UInt32 (buff, (uint32)s); }
00407   static CS_FORCEINLINE void UInt64 (void *buff, uint64 s)
00408   {
00409   #ifdef CS_STRICT_ALIGNMENT
00410     memcpy (buff, &s, sizeof (s));
00411   #else
00412     *((uint64 *)buff) = s;
00413   #endif
00414   }
00415   static CS_FORCEINLINE void Int64  (void *buff, int64 s)
00416   { UInt64 (buff, (uint64)s); }
00418 };
00419 
00420 
00421 /*
00422     To be able to painlessly transfer files betwen platforms, we should
00423     avoid using native floating-point format. Here are a couple of routines
00424     that are guaranteed to work on all platforms.
00425 
00426     The floating point is converted to a fixed 1.7.25 bits format
00427     (one bit sign, 7 bits exponent, 25 bits mantissa) and back,
00428     so that we can binary store floating-point number without
00429     cross-platform problems. If you wonder why 1+7+25 = 33 while we
00430     only have 32 bits, we'll ommit the most significant bit of mantissa
00431     since it is always 1 (we use normalized numbers). This increases the
00432     precision twice.
00433 
00434     For double, we use one bit sign, 15 bits exponent, 49 bits mantissa.
00435 */
00436 
00442 CS_DEPRECATED_METHOD_MSG("Use csIEEEfloat methods instead")
00443 static inline int32 csFloatToLong (float f)
00444 {
00445   int exp;
00446   int32 mant = csQroundSure (frexp (f, &exp) * 0x1000000);
00447   int32 sign = mant & 0x80000000;
00448   if (mant < 0) mant = -mant;
00449   if (exp > 63) exp = 63; else if (exp < -64) exp = -64;
00450   return sign | ((exp & 0x7f) << 24) | (mant & 0xffffff);
00451 }
00452 
00458 CS_DEPRECATED_METHOD_MSG("Use csIEEEfloat methods instead")
00459 static inline float csLongToFloat (int32 l)
00460 {
00461   int exp = (l >> 24) & 0x7f;
00462   if (exp & 0x40) exp = exp | ~0x7f;
00463   float mant = float (l & 0x00ffffff) / 0x1000000;
00464   if (l & 0x80000000) mant = -mant;
00465   return (float) ldexp (mant, exp);
00466 }
00467 
00468 /* Implementation note: csDoubleToLongLong() and csLongLongToDouble()
00469  *
00470  * We avoid use of CONST_INT64() because 64-bit constants are illegal with g++
00471  * under -ansi -pedantic, and we want this header to be useful to external
00472  * projects which use -ansi -pedantic.  Instead, we use bit shifts, such as (1
00473  * << 59), and construct `mask' manually.
00474  */
00475 
00481 CS_DEPRECATED_METHOD_MSG("Use csIEEEfloat methods instead")
00482 static inline int64 csDoubleToLongLong (double d)
00483 {
00484   int exp;
00485   int64 mant = (int64) (frexp (d, &exp) * ((int64)1 << 48));
00486   int64 sign = mant & ((int64)1 << 59);
00487   if (mant < 0) mant = -mant;
00488   if (exp > 32767) exp = 32767; else if (exp < -32768) exp = -32768;
00489   int64 const mask = ((uint64)0xffff << 32) | (uint64)0xffffffff;
00490   return sign | ((int64 (exp) & 0x7fff) << 48) | (mant & mask);
00491 }
00492 
00498 CS_DEPRECATED_METHOD_MSG("Use csIEEEfloat methods instead")
00499 static inline double csLongLongToDouble (int64 i)
00500 {
00501   int exp = (i >> 48) & 0x7fff;
00502   if (exp & 0x4000) exp = exp | ~0x7fff;
00503   int64 const mask = ((uint64)0xffff << 32) | (uint64)0xffffffff;
00504   double mant = double (i & mask) / ((int64)1 << 48);
00505   if (i & ((int64)1 << 59)) mant = -mant;
00506   return ldexp (mant, exp);
00507 }
00508 
00509 /* *\name Floating point conversions
00510  * These routines are used for converting floating-point numbers
00511  * into 16-bit shorts and back. This is useful for low-precision data.
00512  * They use the 1.4.12 format. The range of numbers that can be represented
00513  * in this format is from 2^-8 to 2^7. The precision for numbers near to
00514  * 2^-8 (0.00390625) is near 0.000001, for numbers near 2^7 (128) is near 0.03.
00515  * @{ */
00516 
00522 CS_DEPRECATED_METHOD_MSG("Use csIEEEfloat methods instead")
00523 static inline short csFloatToShort (float f)
00524 {
00525   int exp;
00526   long mant = csQroundSure (frexp (f, &exp) * 0x1000);
00527   long sign = mant & 0x8000;
00528   if (mant < 0) mant = -mant;
00529   if (exp > 7) mant = 0x7ff, exp = 7; else if (exp < -8) mant = 0, exp = -8;
00530   return short(sign | ((exp & 0xf) << 11) | (mant & 0x7ff));
00531 }
00532 
00538 CS_DEPRECATED_METHOD_MSG("Use csIEEEfloat methods instead")
00539 static inline float csShortToFloat (short s)
00540 {
00541   int exp = (s >> 11) & 0xf;
00542   if (exp & 0x8) exp = exp | ~0xf;
00543   float mant = float ((s & 0x07ff) | 0x0800) / 0x1000;
00544   if (s & 0x8000) mant = -mant;
00545   return (float) ldexp (mant, exp);
00546 }
00547 
00555 #endif // __CS_CSENDIAN_H__

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